Twice-yearly HIV drug 100% effective at preventing spread

The development of once-a-day pre-exposure prophylaxis (PrEP), drugs like and Descovy signified a huge advance in . When taken as prescribed by someone who’s HIV-negative, PrEP reduces their risk of contracting the virus from sex by . Now, the results of Phase 3 clinical trials undertaken by have demonstrated that their new injectable PrEP medication, given just twice a year, is 100% effective in preventing HIV spread.

“With zero infections and 100% efficacy, twice-yearly lenacapavir has demonstrated its potential as an important new tool to help prevent HIV infections,” said Merdad Parsey, MD, PhD, Gilead Sciences’ Chief Medical Officer. “We look forward to additional results from the ongoing and continuing our goal of helping to end the HIV epidemic for everyone, everywhere.” Lenacapavir is what’s called a capsid inhibitor.

In the HIV type 1 (HIV-1) virus, the capsid is a protein shell that houses and protects viral genetic material and is crucial for transporting the virus into a host cell. Once inside the host cell, the capsid is shed, and the virus begins copying itself. Lenacapavir stops that from happening.

Truvada and Descovy, on the other hand, are nucleoside reverse transcriptase inhibitors (NRTIs) and prevent sexually acquired HIV infection via a different mechanism. They block reverse transcriptase, an enzyme the virus uses to replicate itself. Both drugs contain a combination of antivirals, emtricitabine and tenofovir, but differ in the form of teno.